Best practice & research. Clinical anaesthesiology
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Although retrobulbar and peribulbar regional anaesthetic techniques are used (by both anaesthesiologists and ophthalmologists) in various types of eye surgery, topical anaesthesia of the conjunctiva and cornea, followed--as needed--by sub-Tenon's block, is now common in routine cataract surgery. Intracameral administration of local anaesthetic by the ophthalmologist is also performed. Sedation during ophthalmic surgery is distinctly lighter than for other surgery because it is essential that the patient remains alert and can cooperate with the surgeon. ⋯ With a catheter placed into the nostril, the patient (whose head is draped and 'hidden') can have the end-tidal CO2 monitored. Finger index (FI), a palpation method that assesses the ease of performing retrobulbar block, is introduced. Because of the risk of life-threatening complications in ophthalmic regional anaesthesia, the services of an anaesthesiologist must be available and training of anaesthesia residents in ophthalmic regional anaesthesia is highly recommended.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewUltrasonography in the current practice of regional anaesthesia.
Ultrasound imaging techniques in regional anaesthesia are becoming a subject of major interest. The quality of blocks and analgesia is relevant to the perioperative outcome of patients and the development of perfect blocks has always been a focus in regional anaesthesia research. ⋯ A second advantage is that the puncture process and the application of medication can be demonstrated and clearly observed during the performance. If there is a problem with the spread or the application, the processing of the block can be immediately modified to improve the quality of the technique.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewNerve stimulation in regional anesthesia: theory and practice.
There is now an accumulation of extensive and varied experience with the use of electrical stimulation for verifying the close approximation of needle and nerve, and for increasing the corresponding success rate. The application of this experience has been of proven benefit in the teaching of regional anesthetic techniques, in the performing of difficult nerve blocks, and in the use of novel accesses, resulting in decreased morbidity and a reduced requirement for local anesthetic. ⋯ Sound knowledge of the anatomy of the area to be blocked, the muscle territory subsidiary to the nerve in question, the applied neurophysiology, and the pharmacology of the local anesthetic used are needed. This chapter reviews the most important aspects, from nerve anatomy and physiology, to electrical features of the needle, and devices used for the updated clinical application of nerve stimulation in the practice of plexus regional anesthesia.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewBupivacaine, levobupivacaine and ropivacaine: are they clinically different?
Two new, long-acting local anaesthetics have been developed after the evidence of bupivacaine-related severe toxicity: levobupivacaine and ropivacaine. Both these agents are pure left-isomers and, based on their three-dimensional structure, they have less toxic potential both on the central nervous system and on the heart. ⋯ Evaluating randomised, controlled trials that have compared these three local anaesthetics, this chapter supports the evidence that both levobupivacaine and ropivacaine have a clinical profile similar to that of racemic bupivacaine, and that the minimal differences observed between the three agents are mainly related to the slightly different anaesthetic potency, with racemic bupivacaine>levobupivacaine>ropivacaine. However, the reduced toxic potential of the two pure left-isomers supports their use in those clinical situations in which the risk of systemic toxicity related to either overdosing or unwanted intravascular injection is high, such as during epidural or peripheral nerve blocks.
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Best Pract Res Clin Anaesthesiol · Jun 2005
ReviewThe pharmacokinetics of ropivacaine in hepatic and renal insufficiency.
In patients with chronic end-stage liver disease, the peak plasma concentrations of ropivacaine after a single intravenous ropivacaine dose are similar to those in healthy subjects. However, patients with end-stage liver disease have about a 60% lower mean ropivacaine clearance than healthy subjects and are thus expected to have over two-fold higher steady-state ropivacaine plasma concentrations during a continuous ropivacaine infusion. ⋯ However, uraemic patients have significantly higher alpha-1-acid glycoprotein plasma concentrations than non-uraemic patients, and the peak plasma concentrations of free ropivacaine (related to toxicity) are similar in both groups. The pharmacokinetics of intravenously administered ropivacaine in patients with renal insufficiency and the possibility of clinically significant (S)-2',6'-pipecoloxylidide metabolite accumulation during continuous or repeated ropivacaine administration in these patients remain to be clarified.